Human skin, as a primary protective barrier, protects the vital organs of the body from external irritants such as changes in temperature and humidity, ultraviolet rays and contaminants, and plays an important role in the regulation of biological homeostasis such as thermoregulation. However, as skin ages, it shows skin aging effects such as loss of elasticity, keratinization, formation of skin wrinkles and skin contraction. The cause of this skin aging can be classified as internal factors such as cell gene transformation and cell tissue change, and external factors such as UV and humidity (Masamitsu Ichihashi, Fragrance Journal, Vol. 32, No. 5, 24-30). In particular, skin aging effect due to UV is called “photoaging”. In photoaging, oxygen free radicals are generated in cells by UV light, and the oxygen free radicals accelerate the synthesis of protease (MMP-1, MMP-3, MMP-9, etc.), enzyme that decomposes protein such as collagen or elastin that is elasticity fiber of derma, by way of the signal transduction system raising an inflammation reaction, and thereby decreasing the elasticity of derma and producing the skin wrinkle.
Therefore, in order to prevent skin aging and keep more healthy and elastic skin, studies have been made to develop physiological active substances having a skin wrinkle improvement effect. For example, in 1995, trans-retinoic acid was approved by FDA as a therapeutic for the improvement of photoaged skin. In addition, retinol, which has fewer side effects, has been used in cosmetics since the mid 1990's, and various cosmetics for skin wrinkle improvement have appeared on the market. Since then, female hormonally active agents or antioxidants extracted from various plants have been introduced to cosmetics as skin wrinkle improving agents.
However, most of the above agents have many problems such as weak efficacy or serious side effects. Thus, extensive studies have been undertaken on substances having an anti-aging effect with no side effects. Among these, there has been much attention on peptides, which have various biological activities, as novel ingredients of highly functional cosmetics. Peptides are biopolymer having 20 essential amino acids linked via amide bond, and it has been expected that peptides would produce direct effects on in vivo metabolism due to their great interaction with protein.
Korean Laid-Open Publication No. 2001-0006358 discloses a cosmetic composition containing protein fraction extracted from the seed of Hibiscus esculentus. Examples are disclosed regarding a process for extracting protein fractions from Hibiscus esculentus and a cosmetic composition containing the protein fraction; however, no use is disclosed of the cosmetic composition containing extracts of Hibiscus esculentus for anti-aging.
Recently, much attention has been paid to the treatment of “expression wrinkle,” which is generated by mechanical movement of facial muscle, as well as to the treatment of endogenous aging generated by aging and of photoaging generated by UV light. With regard to the improvement of expression wrinkle, botulic toxin (Botox), which inhibits acetylcholine secretion in neuron tissue and thereby paralyzes muscle contraction, has been used. However, injection by doctors is required due to its toxicity, and it is prohibited from being used as in cosmetics. Therefore, extensive studies have been made on cosmetics derived from natural plants that can replace Botox and guarantee safety to skin.
Therefore, the present inventors have studied the development of cosmetic materials derived from natural plants not inducing any side effect to skin and having excellent effects in skin aging prevention and skin wrinkle improvement, and have found that a skin-aging cosmetic composition having excellent effects in skin aging prevention and skin wrinkle improvement can be made by containing Hibiscus esculentus extracts, which improve skin wrinkles by inhibiting muscle contraction and removing oxygen free radicals, and active ingredients selected from oleanolic acid, ursolic acid, glycyrrhetinic acid and retinol, which improve skin wrinkles generated by aging.
The Hibiscus esculentus extracts can comprise oligopeptides extracted from Hibiscus esculentus and processed, as active ingredients.
The object of the present invention is to provide an anti-aging cosmetic composition having excellent skin safety and excellent effects in skin aging prevention and skin wrinkle improvement.